This presentation provides the chemistry
student with several example problems to
become more proficient at working with chemical
equations and chemical reactions.
Click on the following hyperlinks for practice.
 Balancing Chemical Equations
 Naming Chemical Reactions
 Predicting Chemical Reactions
Balancing chemical equations is an important step towards
accurately predicting the outcome of a chemical reaction.
Let’s start by reviewing some of the basic parts of a
chemical equation.
Na + Cl  NaCl
Write the chemical equation above on your worksheet.
Draw a circle around the reactants, then a box around the
product.
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Recall that a balanced chemical equation has the same
number and type of atoms on the reactant side of the
equation as on the product side. For example:
Na + Cl  NaCl
There is one sodium and one chlorine atom on the
product side, and the same on the reactant side.
If the chemical equation isn’t in balance then we can
balance it by multiplying either the products or reactants
by a whole number “coefficient”. Write down the
following chemical equation in you worksheet and
balance it.
2H
H2 + O2  H
2H
2O
2O
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Write the following chemical equations on your worksheet
and practice balancing them.
NN2 2++3H
H2  NH
2NH
33
N2H4 +O2  N2 + 2H
H2O
2O
6Na
Na + N2  Na
2Na
3N
3N
2Ca
Ca++2H
H2O  2CaOH
CaOH ++HH2 2
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If you didn’t balance all of the previous chemical equations
correctly, be sure to look in you book for more examples
and continue to practice.
Now let’s work ahead to another important skill in working
in chemistry: Classifying Chemical Reactions.
There are six main classifications chemists assign to
different chemical reactions they are:
- Exothermic
- Endothermic
- Combination
- Decomposition
- Single Replacement - Double Replacement
Take of few minutes to read your assigned classification
type in section 10.3 before moving on with this
presentation.
Continue
The next 6 slides contain six different chemical equations.
Write the chemical reactions on your worksheet and
identify them as exothermic, endothermic, combination,
decomposition, single replacement, or double replacement.
F + MgCl2  MgF + Cl2
Single Replacement
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Write the chemical reaction on your worksheet and
identify it as exothermic, endothermic, combination,
decomposition, single replacement, or double replacement
KCO3 + energy  KO + CO2
Endothermic
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Write the chemical reaction on your worksheet and
identify it as exothermic, endothermic, combination,
decomposition, single replacement, or double replacement
Ag(NO3) + Cu(SO4)  Ag(SO4) + Cu(NO3)
Double Replacement
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Write the chemical reaction on your worksheet and identify
it as exothermic, endothermic, combination,
decomposition, single replacement, or double replacement
NaCl  Na +Cl
Decomposition
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Write the chemical reaction on your worksheet and identify
it as exothermic, endothermic, combination,
decomposition, single replacement, or double replacement
CH4 + O2  CO2 + H2O + energy
Exothermic
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Write the chemical reaction on your worksheet and identify
it as exothermic, endothermic, combination, decomposition,
single replacement, or double replacement
H2 + O2  H2O
Combination
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Let’s now consider the power of a balanced chemical
equation.
2H2 + O2  2H2O
The coefficients in front of each term tell a short and
simple story about the amount of reactants needed to mix
together in order to get an amount of product out.
The link between the balanced chemical equation and the
amount of matter need to mix or that is produced is the
MOLE = 6.022 x 1023 things
In the above chemical reaction – 2 moles of Dihydrogen
are mixed with 1 mole of Dioxide to produce 2 moles of
Dihydrogenmonoxide (water.) Yahoo!
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Write the following chemical equation on your
worksheet and balance it.
CH4 + O2  CO2 + H2O
How many moles of the reactant, O2 are needed to
produce 1 mole of CO2?
2 moles O2 are needed to produce 1 mole of CO2.
How many moles of H2O are produced when 2 moles of
CH4 are placed into the reaction?
4 moles of H2O are produced.
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You have finished this presentation of chemical
equations and reactions. Now Turn to section 10.3
review in your text and answer questions 1 through 4.